Will we see a MetroPCS iPhone tomorrow?

On Wednesday, T-Mobile(s tmus) will hold its first big press conference since it merged with MetroPCS, and though it hasn’t revealed exactly what it plans to announce, there’s a good chance we’ll see the first MetroPCS iPhone.

MetroPCS is notable because it is the largest U.S. operator that hasn’t joined the iPhone party, even though many smaller regional operators like nTelos and Cellcom have scored the iconic Apple device in recent years. Even its parent T-Mobile, which went iPhone-less for nearly six years, started selling the handset in April. Apple(s aapl) isn’t exactly snubbing MetroPCS, but due to the funky configuration of the MetroPCS networks, no single iPhone variant could support both Metro’s 2G CDMA and 4G LTE networks.

I predicted last year that one of the benefits of the merger for MetroPCS would be iPhone support. There are a lot of signs that support is coming sooner than later:

  • T-Mobile is quickly integrating MetroPCS operations with its own. It’s already begun selling Metro customers devices that will work on T-Mobile’s HSPA+ and LTE networks. And we might even see T-Mobile announce on Wednesday that Metro will stop selling CDMA devices completely. That would mean that T-Mo would have to build a new MetroPCS device portfolio composed of devices optimized for its GSM, HSPA+ and LTE networks – one of which is the iPhone.
  • MetroPCS isn’t just selling low-end GSM smartphones and feature phones. On Monday its started selling the T-Mo version of the Samsung Galaxy S 4. The $549 price tag may be a bit steep for many of Metro’s prepaid customers, but T-Mobile is demonstrating that it isn’t reserving the latest and greatest devices for its main brand.
  • Technically MetroPCS is already supporting the iPhone. When it launched its GSM device pilot it began inviting customers with unlocked GSM devices to activate their phones on its network. That includes the iPhone 5 and previous generations of the device. Previously Metro couldn’t support bring-your-own-device plans because it didn’t offer SIM cards. That’s rapidly changing.

Assuming this actually happens, the iPhone 5’s $650 to $850 unsubsidized price might make it a difficult sell, given Metro’s core focus on budget-minded consumers. MetroPCS could take a page from fellow no-contract prepaid provider Cricket Communications’(s leap) book and offer a discounted version of the device ($500) to lure in customers. I wouldn’t expect anything more than a moderate discount though. Anything more would go against T-Mobile’s new policy of no longer subsidizing devices.

The iPhone 4 and iPhone 4S would also be much cheaper alternatives, although those handsets wouldn’t be able to connect to all of T-Mobile’s HSPA+ networks or its new LTE systems. There’s also a good chance that the iPhone 5 will soon be discounted as Apple prepares to refresh its smartphone line later this year.

If customers can stomach an older device or shell out the dough for a new iPhone 5, though, they could get some of the cheapest smartphone service plans in the business. MetroPCS plans start off at $40 a month for unlimited talk and text as well as 500 MB of data before throttling kicks in. T-Mobile, which is already the most inexpensive of the major operators, offers the same plan for $10 more a month.